Adjustable cam for circular knitting machines



July 15, 1958 v. H. BUTLER ADJUSTABLE CAM FOR CIRCULAR KNITTING MACHINES Filed May 14, 1957 INVENTOR VAUGHN H. BUTLER BY l ATTORNE llnited States Patent ADJUSTABLE CAM FOR CIRCULAR KNITTIN MACHINES Vaughn H. Butler, Harriman, Tenn., assignor to Burling= ton Industries, Inc., Greensboro, N. C., a corporation of Delaware Application May 14, 1957, Serial No. 659,1?43

3 Claims. (Cl. 66-156) This invention relates to circular knitting machines, and in particular to actuating cams used on the drums thereof. The invention relates specifically to drum cams of novel structure, permitting ready adjustment of the effective length and end position of the cams.

As is well known, conventional circular knitting machines are provided with one or more drums, which are advanced or jogged at intervals throughout the knitting cycle, and serve by means of cams mounted thereon, to actuate thrust bars, bell cranks, and other machine elements, which in turn actuate various elements of the chine, such as the yarn fingers, needle cams and the like, in proper timing and sequence.

The actuating cams mounted on the drum must be of suitable size and shape, and for precise timing, must be precisely sized and located. The actuating cams are commonly mounted on the drum by screws extending therethrough into tapped holes in the drum. In setting up the machine, each actuating cam is selected and located, and then fixedly mounted by drilling and tapping a hole in the drum at the proper position and screwing the cam to the drum. In resetting or adjusting the machine, it is frequently necessary to replace and/or positionally adjust a cam, tovary its operative length or an end position thereof.

Circular knitting machines continue to grow more versatile and complex, and additional functions and operations are frequently added thereto For such purposes, additional thrust bars, bell cranks and the like are mounted on the machine, and actuating cams therefor are mounted on the drums. Standard circular knitting machines customarily provide additional space on the drums thereof for such purpose. For multiple feed knitting, needle cam operation, eyelet closing and similar functions, timing is frequently critical, and actuating cam adjustment for optimum operation is a common necessity. The trailing end position of the actuating cams is very frequently critical to attain proper operational timing.

In order to alter or adjust an actuating earn, it has hitherto been necessary to remove the cam from the drum. The cam may be replaced by another cam of more suitable shape or size, or for particular operations, the machine fixer commonly resorts to grinding of the cam to reduce its size, or to welding, brazing, and shaping, to build it up. To relocate the cam, a new screw hole must be drilled and tapped, and sometimes an old hole must first be filled.

A principal object of the present invention is to provide an adjustable drum cam, which may be quickly varied in elfective length, while mounted on the machine drum. A related object is to provide a novel actuating cam structure, permitting positional adjustment of the cam end, in particular the trailing cam end, with minimum effort. Further objects will be in part obvious and in part pointed out hereinafter.

The invention and the novel features thereof may best ice be made clear from the following description and the accompanying drawing, in which:

Figure 1 is atop plan view of a preferred embodiment of the present invention, and

Figure 2 is a sectional view taken on line 22 of Figure 1, and showing the cam in operational relationship with an exemplary thrust bar,

Referring to the drawings, 10 represents a segment of a drum of a circular knitting machine. Mounted on the drum is an actuating cam indicated generally at 11, and comprising an underlying arcuate member 12 and an overlying arcuate member 13. The underlying arcuate member 12 is adapted to fit closely against the outer periphery of the rotary drum, and the overlying mernber 13 is correspondingly shaped. A cam section 14 extends radially outwardly from an end of the underlying member 12, preferably from the trailing end thereof, as shown, this cam section having a high actuating surface 15 and a sloping surface 16 descending therefrom. As will be understood, the sloping surface 16 is not essential, and the cam may drop off abruptly from the operating surface 15. From the corresponding end of the overlying member 13, a cooperative cam section 17 extends radially outwardly, terminating in an operating surface 18 substantially co-planar and cooperative with the operating surface 15. A sloping surface 19 may lead upwardly to the operating surface 13 of the overlying member 13. At their ends opposite the cam sections, the cam members are desirably provided with inclined surfaces 29 and 21. The overlying cam member 13 is apertured at 22, and the outer end of the aperture may be countersunk as at 23 to accommodate the head of the fiathead screw 24. The underlying cam member 12 is slotted at 25, the width of the slot being substantially the diameter of bore 22, and the length of the slot, which is disposed longitudinally of this member, being somewhat greater. In Figure 2, the lower end of a thrust bar 26 is illustrated riding the operative surfaces 15 andlfi of the cam members.

In utilizing the cam, the cam sections are preferably assembled in the relationship illustrated in the drawing, with the bore 22 aligned substantially with the center of the slot 25. The cam is then positioned as accurately as possible on the drum 1t and a hole 27 drilled in the drum in alignment with the bore 22. The hole 27 is tapped, and the screw 24 may then be passed through the bore of the overlying cam member and the slot of the underlying cam member and threaded into the drum. The cam may be fixedly mounted in place by tightening the screw. In operation, as the drum advances in the direction of arrow 28, the thrust bar 26, which is constantly urged against the drum periphery as by a spring, is preliminarily caused to ride up the inclined surfaces 20 and 21 of the cam, onto the intermediate upper surface of the overlying cam member and the head of screw 24. This movement of the thrust bar may constitute the initial step of a stepwise actuation, or may merely position the thrust bar for subsequent actuation. The next jog or further movement of the drum carries the cam further under the thrust bar, causing the thrust bar to ride up the inclined surface 15 of the cam section 17, and onto the actuating surfaces 18 and 1% of the cam sections 17 and 14, respectively. This represents the final actuation position of the thrust bar. As will be evident, a small space between the cam sections 14 and 17 has no effect on the cam operation.

The drum jog which carries the thrust bar 26 up onto the actuating surfaces 15 and 18 may carry the cam completely out from under the thrust bar, whereupon the thrust bar is actuated only momentarily, and then rides down the cam surface 16 and back onto the drum. In this case, the effective length of the cam is critical, and controls the period of actuation of the thrust bar. The

effective length of the cam, as Will be understood, may be considered the distance from the leading edge of surface 18 of cam section 17 to the trailing edge of actuating surface 15 of cam section 14. In accordance with the present invention, the effective length of the cam may be quickly and easily varied in either direction. For example, if it be desired to increase the effective length of the cam, it is necessary only to loosen the screw 24 with a screw driver, move the underlying member 12 to the left, as viewed in the drawing, an appropriate distance, and then tighten the screw 24, thereby again locking both parts of the cam in place. The overlying cam member, in the illustrated embodiment, is relatively immovable. The underlying cam member may then assume a position such as the dotted line position illustrated in Figure 2 and indicated by the numeral 29. The limit of movement of the underlying cam member in this direction is, of course, determined by the length and position of its slot 25. To decrease the efitective length of the cam, the underlying cam member may be relatively displaced to the right in the same manner, and may be adjusted in this direction until the cam sections 14 and 17 meet.

In many operations, the associated thrust rod will rest on the operating surfaces 15 and 18 for an extended period, while the drum is at rest, and will descend the sloping surface 16 and ride off the cam on the next rotational movement of the drum. In such cases also, the relative timing of the movement of the thrust bar with the jog of the drum may be exceedingly critical. It will be evident that this timing also may be altered, within limits, by positional adjustment of the trailing end of the cam section 14, in particular the trailing edge of the operating surface thereof. In all cases, the adjustment may be made Without removing the cam from the drum, requiring only a screw driver. The adjustment is so quick and easy that repeated adjustments may be made while checking the operation of the machine, until perfect timing as achieved.

While the embodiment illustrated and described is preferred, it will be recognized that in some applications the underlying cam member may be apertured and the overlying cam member slotted.

It will thus be seen that there has been provided by this invention a structure in which the various objects hereinbefore set forth, together with many practical advatages, are successfully achieved. As various possible embodiments may be made of the mechanical features of the above invention, all without departing from the scope thereof, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative, and not in a limiting sense.

I claim:

1. In a circular knitting machine, a rotary drum and an actuating cam mounted peripherally thereon, said cam including overlying and underlying members, cooperative cam sections extending radially outwardly from corresponding ends of said members, one of said members being slotted and the other being apertured, and a screw extending through said members into said drum, whereby said apertured member may be fixedly mounted on said drum and said slotted member may be positionally adjusted with respect to said apertured member and said drum.

2. In a circular knitting machine, a rotary drum and an actuating cam mounted peripherally thereon, said cam including overlying and underlying members, cooperative cam sections extending radially outwardly from corresponding ends of said members, said overlying member being apertured and said underlying member being slotted, and a screw extending through said members into said drum, whereby said overlying member may be fixedly mounted on said drum and said underlying member may be positionally adjusted with respect to said apertured member and said drum.

3. In a circular knitting machine, a rotary drum and an actuating cam mounted peripherally thereon, said cam including overlying and underlying arcuate members, cooperative cam sections extending radially outwardly from the trailing ends of said members, said overlying member being apertured and said underlying member being longitudinally slotted, and a screw extending through said members into said drum, whereby said overlying member may be fixedly mounted on said drum and said underlying member may be adjusted with respect thereto in the direction of drum rotation.

References Cited in the file of this patent UNITED STATES PATENTS 

